Apparatus for forming a fibrous laminated material

ABSTRACT

This invention relates to a fibrous laminated material wherein a first fibrous layer comprising a plurality of staple fibers or continuous filaments of a thermoplastic material and a second fibrous layer comprising a plurality of staple fibers or continuous filaments of two or more thermoplastic or other materials are bonded together in a spaced apart bonding pattern having apertures formed therein to form a fibrous laminate having improved liquid distribution and management properties as well as enhanced comfort and softness when placed in contact with human skin. Also disclosed are a method and apparatus for making such a fibrous laminate.

This application is a continuation of application Ser. No. 08/353,581entitled "Fibrous Laminated Web And Method And Apparatus For Making TheSame" and filed in the U.S. Patent and Trademark Office on Dec. 12,1994, now abandoned, which is a continuation application of U.S. Ser.No. 07/973,146 entitled "Fibrous Laminated Web And Method And Apparatusfor Making The Same" and filed in the U.S. Patent and Trademark Officeon Nov. 6, 1992 now abandoned. The entirety of these Applications ishereby incorporated by reference.

BACKGROUND OF THE INVENTION

This invention generally relates to fibrous web laminates suitable foruse in articles used to absorb, distribute and retain body liquids, suchas disposable diapers, sanitary napkins, incontinence garments and thelike, and to a method and apparatus for making same. More specifically,this invention relates to a nonwoven laminated material having improvedliquid distribution and management and air circulation properties aswell as enhanced comfort and softness when placed in contact with humanskin.

Nonwoven materials, such as spunbonded webs and carded webs, have beenused as bodyside liners in disposable absorbent articles. Typically,very open, porous liner structures have been employed to allow liquid topass through them rapidly, thereby keeping the wearer's skin separatefrom the wetted absorbent core underneath the liner. Also, other layersof material, such as those constructed with thick, lofty fabricstructures, have been interposed between the liner and absorbent pad forthe purpose of reducing flowback.

U.S. Pat. No. 4,761,322 to Raley discloses a fibrous web laminatewherein a fibrous layer having a soft texture is laminated with acontiguous layer having a greater structural integrity such that thesoft texture layer may be utilized as a skin-contacting surface and thecontiguous layer thereto may provide mechanical strength and integrityto the laminate. The laminate of this patent includes a first fibrouslayer, which is pattern bonded in a first spaced-apart bonding pattern,formed, for example, by passing the first layer through the nip formedby a first heated pattern roll and a smooth roll, and a second fibrouslayer, which is pattern bonded in a second spaced-apart bonding pattern,formed, for example, by passing the first and second layers through thenip formed by a second heated pattern roll and a smooth roll. The secondbonding pattern further produces bonds between the first and secondlayers, while the first bonding pattern does not.

U.S. Pat. No. 4,392,862 to Marsan et al. discloses an absorptive deviceincluding a facing element, a support element, an absorbent core and abacksheet. The facing element is a fluid permeable, unbonded, carded webof hydrophobic, thermoplastic fibers. The facing element is bonded inspaced apart bonding regions to a fluid permeable support element ofnonwoven polyester or monofilament scrim.

U.S. Pat. No. 4,088,726 to Cumbers discloses a method of making nonwovenfabrics wherein a nonwoven web of thermally bondable material is passedthrough a nip between co-operating calender rolls, at least one of whichis heated, with one calender roll having a surface pattern consisting ofcontinuous lands and the other calender roll having a surface patternconsisting of lands that are isolated projections and the centroids ofarea of those projections concurrently in the nip being disposed atdiffering distances from the longitudinal axis of the nearest continuousland surface so that lands that oppose each other in the nip overlap todifferent extents.

Notwithstanding the development of nonwoven materials of the typesdescribed above, the need remains for a nonwoven material that canprovide improved liquid intake and distribution as well as aircirculation when used as a body contacting layer in a disposableabsorbent article, resulting in greater surface dryness and comfort forthe wearer's skin. There also is a need for a nonwoven material thatexhibits improved softness and comfort when placed in contact with thewearer's skin.

SUMMARY OF THE INVENTION

This invention relates to a nonwoven laminated material wherein a firstnonwoven layer comprising a plurality of staple fibers or continuousfilaments of a thermoplastic material and a second nonwoven layercomprising a plurality of staple fibers or continuous filaments of twoor more thermoplastic materials are bonded together in a spaced apartbonding pattern having apertures formed therein to form a nonwovenlaminate having improved liquid distribution and management propertiesas well as enhanced comfort and softness when placed in contact withhuman skin. Also disclosed are a method and apparatus for making such anonwoven laminate.

BRIEF DESCRIPTION OF THE DRAWINGS

The nonwoven laminated material of this invention will be betterunderstood by reference to the following description of an embodiment ofthe invention taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective partial sectional view of a nonwoven laminatedmaterial according to the present invention;

FIG. 2 is a cross-sectional elevational view of the nonwoven laminatedmaterial of FIG. 1 taken along line A--A of FIG. 1;

FIG. 3 is a schematic diagram showing process apparatus for forming anonwoven laminated material in accordance with the present invention;

FIG. 3a is a perspective view of thermal bonding rolls for forming anonwoven laminated material in accordance with the present invention;

FIGS. 3b and 3c are enlarged views of portions of the outer surfaces ofthe thermal bonding rolls of FIG. 3a;

FIG. 4 is a cross-sectional view through a disposable diaper includingthe nonwoven laminated material of the present invention positioned onthe side of the diaper that will be placed next to the infant's body;

FIG. 5 is a photomicrograph (13.2 magnification, 12 mm working distance,5 KV accelerating voltage) of a portion of the apertured bonding regionof the nonwoven laminated material of the present invention, with thefirst layer of the nonwoven laminated material facing the viewer; and

FIG. 6 is a photomicrograph (28.7 magnification, 12 mm working distance,5 KV accelerating voltage) of a portion of the apertured bonding regionof the nonwoven laminated material of the present invention, with thesecond layer of the nonwoven laminated material facing the viewer.

FIG. 7 is a perspective view of a testing apparatus used to evaluatefluid intake and flowback of nonwoven laminated materials of the typedescribed herein;

FIG. 8 is a cross-sectional view of FIG. 7;

FIG. 9 is a perspective view showing a fluid flowback testing apparatusused to evaluate nonwoven laminated materials of the type describedherein; and

FIG. 10 is a cross-sectional view of FIG. 9.

DETAILED DESCRIPTION

The present invention comprehends a laminated fibrous fabric or materialhaving a first fibrous layer comprising a plurality of staple fibers orcontinuous filaments of one or more thermoplastic materials and a secondfibrous layer comprising a plurality of staple fibers or continuousfilaments of two or more thermoplastic materials. The first layer andsecond layer, which can be nonwoven webs, are formed into a fibrouslaminate by a spaced apart bonding pattern, such as by thermal bondingbetween a pair of heated embossing or bonding rolls having raisedbonding patterns on the outer surfaces thereof. This spaced apartbonding pattern provides high structural integrity between the first andsecond layers without compromising the flexibility and soft surfacetexture of the first layer or the loftiness of the resulting fibrouslaminate. Apertures are formed in the spaced apart bonding areas toenhance liquid distribution and air circulation through the respectivelayers of the fibrous laminate. The fibrous laminate formed inaccordance with the present invention exhibits improved liquid intakeand distribution and air circulation characteristics, resulting ingreater surface dryness and comfort when placed against human skin. Thefibrous laminate of this invention further provides a lofty, pillowedstructure that exhibits improved softness and cushiony feel to the user.Other attributes and advantages of the present invention will beapparent from the ensuing disclosure and appended claims.

As used herein, the terms "nonwoven web" and "nonwoven layer" mean afibrous web or layer having a structure of individual fibers orfilaments that are interlaid in a random pattern. Nonwoven webs havebeen formed in the past, as known to those of ordinary skill in the art,by a variety of processes, such as, for example, meltblowing,spunbonding, air-laying, wet-laying, dry-laying, dry staple and cardedweb processes. While nonwoven webs can be used in practicing the presentinvention, the invention is not to be considered limited to nonwovenmaterials and other suitable fibrous structures may be employed.

The fibrous laminated material of this invention will be describedherein in connection with its use in disposable absorbent articles,however, it should be understood that potential applications of thisinvention need not be limited to such disposable absorbent articles. Asused herein, the term "disposable absorbent article" means an articlethat is used to absorb and retain body exudates and is intended to bediscarded after a limited period of use. Such articles can be placedagainst or in close proximity to the body of the wearer to absorb andretain various exudates discharged from the body.

Referring now to FIG. 1, a perspective partial sectional view of anembodiment of the present invention is shown. The nonwoven material 10comprises a first nonwoven layer 12 and a second nonwoven layer 22. Thefirst layer 12 has an upper surface 14 and a lower surface 16 and thesecond layer 22 has an upper surface 24 and a lower surface 26. In theembodiment shown, a plurality of thermal fusion bonds in a spaced apartbonding pattern 18 extend through the thickness of the nonwoven material10 to thermally fuse or bond fibers of first layer 12 with fibers ofsecond layer 22 at the interface 20 therebetween. Bonding of the firstand second layers is substantially limited to the bonding regions 18.That is, in the areas 19 of the first and second layers outside of thebonding pattern 18, the fibers of the respective layers are only lightlybonded to one another by fiber fusing from thermal energy. Thus, thebonding regions 18 are separated or "spaced apart" by lightly bondedareas 19. Also as shown in this embodiment, apertures 30 are formedwithin the bonding areas 18 to improve the liquid distribution rate andair circulation of the nonwoven material 10.

The respective first and second fibrous layers of the present inventionmay be formed by any suitable natural or synthetic fibers in anyappropriate structure, although in the embodiments shown in theaccompanying drawings, these fibers are formed into nonwoven layers. Ingeneral, each nonwoven layer of the present invention can be preparedfrom noncontinuous fibers, continuous filaments or a combinationthereof. The method of producing each layer in the embodiment shownemploys dry staple processes, or more specifically, carded webtechniques, as known to those of ordinary skill in the art. While cardedweb techniques can be advantageously employed in forming the respectivelayers of the present invention, spunbonding, meltblowing, air-layingand other techniques known to those of ordinary skill in the art thatproduce noncontinuous fibers and continuous filaments are alsoconsidered within the scope of this invention. Carded webs suitable foruse in the practice of the present invention can have the fibers in analigned or an unaligned configuration. Conventional carding machines, asknown to those of ordinary skill in the art, can be employed inproducing the respective layers of the present invention.

Commercially available thermoplastic polymeric materials can beadvantageously employed in both layers of the present invention.Examples of such polymers, by way of illustration only, includepolyolefins, polyamides, polyesters and the like. The fibers may haveany suitable morphology and may include hollow or core fibers, shapedfibers, bicomponent fibers or high absorbent particle impregnatedfibers.

In the embodiment shown in FIG. 1, the first nonwoven layer 12 of thenonwoven fabric 10 is a bonded carded web made of thermoplasticpolypropylene fibers. The second nonwoven layer 22 of the nonwovenfabric is a substantially unbonded or unbonded carded web made of ablend of polypropylene and polyester fibers. By "substantially unbonded"as used herein is meant a web with fibers that are sufficiently bondedtogether, by known bonding processes, for handling the web, butinsufficiently bonded to provide the needed strength and integrity forthe end-use application. By "unbonded" as used herein is meant a webwith fibers that are not mechanically, thermally nor chemically bondedtogether.

The ratio of different thermoplastic fibers in the second layer 22 canbe varied as appropriate for the intended end-use application of thenonwoven material. For example, the ratio of polypropylene to polyesterfibers by total weight of the second layer 22 can range from about 70:30to about 25:75, with about 40:60 being the ratio for the embodimentshown.

It is an important advantage of the present invention that certainmaterials that might not have optimum properties in a nonwoven web forvarious reasons may be used in the present invention in combination witha web made from one or more different materials to produce a better setof properties. For example, an unbonded or substantially unbondednonwoven layer of polypropylene and polyester fibers may be consideredtoo soft and weak for certain nonwoven web applications. However, infollowing the teachings of the present invention, a nonwoven layer madeof an appropriate blend of polypropylene and polyester fibers can bebonded to a stronger nonwoven web, such as a bonded layer ofpolypropylene fibers, to thereby make a more desirable nonwovenlaminate.

The fiber sizes, basis weights and densities of the fibrous layerscomprising the nonwoven fabric 10 of the present invention also can bereadily varied depending on the intended use of the web. For example, inone application of the present invention, the nonwoven material can beused as a body facing layer for a disposable absorbent article having anabsorbent core placed between the liner and an outer cover. Suchdisposable articles include, by way of illustration only, diapers,training pants, sanitary napkins, incontinence garments and the like.For this application, the polypropylene fibers of the first layer 12 canbe as fine as about 1.0 denier (12.5 μm in diameter) to as coarse asabout 3.0 denier (21.6 μm) and have a crimped fiber length of from about1.25 in. (31.75 mm) to about 2.5 in. (63.5 mm), although it isdesireable for the user's comfort that the fibers be from about 2 denier(17.6 μm) to about 2.2 denier (18.5 μm) and have a crimped fiber lengthof about 1.5 in (38.1 mm). (It is known in the art that crimping is afunction of fiber type, diameter and density.) The finer fiber size ofthe polypropylene fibers in the first layer 12, which in thisapplication comes into contact with human skin and functions as a linerlayer, yields a softer surface texture for the first layer 12. Thepolypropylene fibers in the second layer 22 can, but need not, beidentical to the polypropylene fibers in the first layer 12. Thepolyester fibers in the second layer can be from about 3 denier (17.5μm) to about 9 denier (30.4 μm) and have a crimped fiber length of fromabout 1.25 in. (31.75 mm) to about 3 in. (76.2 mm), with polyesterfibers of 6 denier (24.8 μm) having a crimped fiber length of about 2in. (50.8 mm) being suitable. While not wishing to be bound by anyparticular theory, it is currently believed that the use of differentfibers enhances the liquid wicking and distribution properties of thesecond layer 22. The fibers in the first layer 12, which have the samediameters, tend to form similarly sized pores in a single plane, whilethe fibers in the second layer 22, which have different diameters, tendto form pores of varying sizes in multiple planes. The differing poresizes in multiple planes in second layer 22 are believed to enhancewicking of liquid throughout the second layer 22 and liquid intake intoand distribution through the second layer 22. It is further currentlybelieved that the resiliency of the polyester fibers is a contributingfactor to the improved liquid management and air circulationcharacteristics of the nonwoven laminate of this invention.Consequently, in this application, the second layer 22 functions as asurge layer or temporary reservoir for the liquid passing through thenonwoven material 10 into the absorbent core of an absorbent article.

The nonwoven material 10 of this invention can have a basis weight fromabout 25 g/m² (0.7 oz/yd²) to about 78 g/m² (2.3 oz./yd²), a thicknessof from about 0.03 in. (0.76 mm) to about 0.08 in. (2.03 mm) and adensity of from about 0.020 g/cc to about 0.050 g/cc. Density isdetermined using the following equation: ##EQU1## For example, in theembodiment shown, the basis weight for the nonwoven web 10 can rangefrom about 47 g/m² (1.4 oz/yd²) to about 58 g/m² (1.7 oz/yd²), thethickness can range from about 0.04 in. (1.02 mm) to about 0.06 in.(1.52 mm) and the density can range from about 0.030 g/cc to about 0.045g/cc.

The basis weight of the nonwoven material 10 was measured using a devicethat measures the weight of a sample of the nonwoven material. Eachsample measured no less than 4 in² (2580 mm²). Each sample was cut,smoothed to eliminate folds or wrinkles, and weighed on an analyticalbalance to the nearest 0.01 g. The basis weight then was calculated bydividing the sample weight by the sample area.

The thickness of the nonwoven material 10 was measured using a devicethat applies a constant loading pressure of 0.05 psi (35.15 kg/m²) to asample of the nonwoven material. Each sample measured at least 5×5 in.(127×127 mm). Each sample was cut out, smoothed to eliminate folds orwrinkles, placed under a circular plexiglass platen (foot) having a 3in. (76.2 mm.) diameter, centered as much as possible, and the platenthen was lowered onto the specimen. The thickness of each sample wasrecorded to the nearest 0.001 in. (0.0254 mm).

Although in alternative embodiments, the basis weight and density of thefirst layer 12 prior to bonding to the second layer 22 can vary inrelation to that of the second layer 22, the embodiment shown includes afirst layer 12 having a lower basis weight and a higher density than thesecond layer 22. The basis weight for the first layer can range fromabout 0.4 oz/yd² (16 g/m²) to about 0.8 oz/yd² (28 g/m²), with about 0.5oz/yd² (18 g/m²) to about 0.6 oz/yd² (22 g/m²) being desireable, and thebasis weight for the second layer can range from about 0.7 oz/yd² (24g/m²) to about 1.02 oz/yd² (35 g/m²), with about 0.9 oz/yd² (32 g/m²)being desireable. The density for the first layer can range from about0.050 g/cc to about 0.065 g/cc, with about 0.055 g/cc being desireable,and the density for the second layer can range from about 0.024 g/cc toabout 0.045 g/cc, with about 0.035 g/cc being desireable.

Referring now to FIG. 2, a cross-sectional view of the embodiment of thenonwoven material 10 of the present invention described above is shown,comprising a first nonwoven layer 12 and a second nonwoven layer 22. Aseries of bonds forming a spaced apart bonding pattern 18 extend throughthe thicknesses of the respective layers and bond the first layer 12 tothe second layer 22 at the interface 20 in the bonding regions 18. Themanner of forming the spaced apart bonding pattern 18 now will bedescribed.

The spaced apart bonding regions 18 may be produced by any suitablemethod of bonding the respective first and second layers to one anotherat the interface 20 therebetween that yields a nonwoven material 10having the liquid management, air circulation and other propertiesdescribed herein. Thermal bonding, which includes the use of a pair ofheated embossing rolls, is considered a useful method of forming thebonding pattern 18, as described in greater detail hereinbelow.

The present invention contemplates bonding of the respective layers invarious sequences. For example, the first layer 12 may be formed andbonded in a first operation, with the second layer 22 formed in a secondoperation and then bonded to the first layer 12 in yet a furtheroperation. Alternatively, the first layer 12 may be formed in a firstoperation, the second layer 22 formed in a second operation, and therespective layers bonded together in still another separate operationwhich simultaneously bonds the fibers in the first layer 12 to oneanother. The thermoplastic fibers of second layer 22, which areinitially unbonded or substantially unbonded, do have a degree ofthermal bonding when formed into the nonwoven laminated material 10, asfurther described below.

In the embodiment shown, the fibers of the first layer 12 have a greaterextent of bonding relative to the fibers of the second layer 22. Forexample, first layer 12 may be thermobonded by passing the layer 12between a pair of bonding rolls of conventional construction (i.e., anengraving roll and a smooth roll) heated to a temperature of between270° F. (132° C.) and 300° F. (149° C.), with 275° F. (135° C.) to 285°F. (141° C.) being desireable. The appropriate temperature for bondinglayer 12 using thermal bonding rolls will vary depending upon therotational surface speeds and diameters of the bonding rolls and thethermoplastic fibers used. The first layer 12 may alternatively bebonded by other known bonding processes, such as by pattern adhesivebonding, needling or hydro or airjet entangling of the fibers. In thisembodiment, the first layer 12 has a higher density than the secondlayer 22. In this way, the first layer 12, which has greater structuralintegrity and mechanical strength than the second layer 22, can providea base substrate for the second layer 22.

The degree of bonding of the first layer 12 to the second layer 22 maybe controlled in the spaced apart bonding region 18 by altering thepercent bond area, which refers to the surface area of the interfacebetween the respective layers that is occupied by bonds within thebonding regions. Thus, as shown in FIGS. 1 and 2, the interface 20 ofthe first layer 12 and second layer 22 has a spaced apart pattern ofbonds 18 disposed across its surface and the ratio of the surface areaoccupied by the bonding regions 18 to the total area of the surface ofthe interface 20 is the percent bond area for the interface 20. In theembodiment shown, the percent bond area of the nonwoven laminate canrange from about 1% to about 6%, with about 2% to about 4% beingdesireable. While a hexagonal (honeycomb-like) bonding pattern is shownin this embodiment, the present invention encompasses other geometric,non-geometric, repeating and non-repeating bonding patterns, which aresuitable for incorporation into the nonwoven material of the presentinvention.

FIG. 3 is a schematic diagram of the apparatus used for forming theabove-described embodiment of the nonwoven laminated material of thepresent invention. As stated above, conventional carding machines, suchas described in U.S. Pat. Nos. 3,604,062 and 3,604,475, can be employedin producing the respective layers of the present invention. As shown,the first carding machine 42 lays down the first layer 12 on a movingbelt 40, while the second carding machine 52 lays down the second layer22 on top of the first layer 12. In this way, first layer 12 acts as abase substrate for second layer 22 as the two layers pass through theforming process.

Optionally, the two layers may be passed through a pair of compactingrollers that slightly compact the fibrous webs to thereby increase theintegrity of the webs and to aid in further processing. One or both ofthe layers also may be passed through apparatus that orients the fibersin the web to optimize material strength in the machine direction (MD)and cross direction (CD). As used herein, machine direction (MD) refersto the direction in which the web was laid down (from left to right inFIG. 3) and cross direction (CD) refers to the axis perpendicular to thedirection in which the web was laid down. MD strength for the nonwovenlaminate of this invention must be sufficiently high (at least about 900g/in. (354 g/cm) to about 2700 g/in. (1062 g/cm), with at least about1300 g/in. (512 g/cm) being desireable) so that the nonwoven webs willnot be broken during high speed manufacturing processes used forproducing disposable absorbent articles, such as diapers.

The two nonwoven layers next pass through the two bonding rolls 60 and70. In the embodiment shown in FIGS. 3 and 3a, both bonding rolls areheated and have raised (male) bonding patterns on the outer surfacesthereof. The lower roll 60 has a spaced apart bonding pattern 62 on itssurface, while the upper roll 70 has raised bonding points 72 on itssurface. In alternative embodiments, the positions of the bonding rollscan be reversed. It is a feature of this invention, therefore, thatthermal bonding rolls having different male or raised bonding patternson each of the outer surfaces thereof are employed to create a spacedapart bonding pattern for bonding together the respective layers of thenonwoven material.

As the two nonwoven layers 12 and 22 pass between these two heated rolls60 and 70, each layer becomes stabilized by the formation of discretecompacted bonding areas 18 of thermally induced fiber bonds that extendthrough a major portion of the thickness of each nonwoven layer. Thethickness of the compacted or bonded regions 18, which may varydepending upon the thicknesses of the respective layers 12 and 22, canrange from about 50 μm to about 150 μm, with about 70 μm to about 110 μmbeing used in the embodiment shown herein. The compacted bonded areas ofnonwoven material 10 are distributed in a bonding pattern 18 formed bythe points of contact between the raised bonding patterns on the twoheated rolls 60 and 70, with lightly bonded fiber spans 19 therebetween.

Apertures 30 are formed in the bonded areas 18 formed by the points ofcontact between the raised patterns on the heated bonding rolls 60 and70, as described in greater detail below. While the exact size and shapeof the apertures 30 are not considered critical by the inventor (seeFIGS. 5 and 6), apertures having average diameters ranging from about 8μm to about 580 μm or more can be advantageously employed in the presentinvention, with aperture average diameters from about 29 μm to about 277μm being desireable. As shown in FIGS. 5 and 6, the apertures 30 aresubstantially free of fibers throughout the thickness of the nonwovenlaminated material 10 and provide a non-tortuous pathway for liquid topass through the nonwoven material 10. The apertures 30, consequently,allow rapid liquid intake through the first layer 12 into the secondlayer 22 and finally into the absorbent core of an absorbent article. Ithas been observed that liquid primarily flows away from the point ofcontact with the nonwoven material 10 along the apertured bondingregions 18, which act as channels for the liquid. The apertures 30 areto be distinguished from the pores formed between fibers in layers 12and 22, which are not sufficiently large nor non-tortuous to allow suchrapid liquid intake and distribution. Consequently, a nonwoven fabric 10is shown having spaced apart bonded areas 18 with lightly bonded areas19 therebetween and apertures 30 formed in the bonded areas 18.

Two parameters of concern in regard to the specific combination ofraised patterns on the bonding rolls that are used are the size of theraised bonding areas of the bonding rolls and the distance or spacingseparating the bonding areas. These two parameters together affect thepercentage of area on the nonwoven material 10 that becomes bonded, asdescribed above. It is important that the percent bond area be greatenough to insure sufficient integrity of the web for its intended use.On the other hand, it is important that the percent bond area not be toogreat, as a higher percent bond area usually produces a web with reducedsoftness. The percent bond area of the lower roll 60 (the ratio of thesurface area of the raised bonding pattern 62 to the total area of theouter surface of lower roll 60) of this embodiment can range from about9% to about 20%, with about 18% to about 19.5% being desireable. Thepercent bond area of the upper roll 70 (the ratio of the surface area ofthe raised bonding points 72 to the total area of the outer surface oflower roll 70) of this embodiment can range from about 10% to about 30%,with about 11% to about 20% being desireable. As noted above, thepercent bond area of the nonwoven laminate 10, which is the mathematicalproduct of the percent bond areas of the upper roll 70 and lower roll60, can range from about 1% to about 6%, with about 2% to about 4% beingdesireable.

It is further important that the raised bonding patterns of the twobonding rolls be combined to optimize the number of apertures within thebonded areas. In the embodiment shown in FIGS. 3a, 3b and 3c, the widthof the raised bonding pattern 62 on the outer surface 64 of the lowerroll 60 can range from about 0.04 in. (1.0 mm.) to about 0.08 in. (2.0mm.), with a width of about 0.07 in. (1.8 mm.) being desireable, and thewidth at the base 66 of the raised bonding pattern 62 can range fromabout 0.06 in. (1.6 mm) to about 0.12 in. (3.1 mm), with about 0.11 in.(2.8 mm) being desireable. The raised bonding pattern 62 of the lowerroll 60 in this embodiment has an engraving depth of about 0.04 in. (1.0mm), which is the distance between the outer surface 64 and base 66 ofthe raised bonding pattern 62. The individual hexagons 68 of the raisedbonding pattern 62 of lower roll 60 can have a repeating width W of fromabout 0.65 in. (16.50 mm) to about 0.68 in. (17.33 mm), a repeatingheight H of from about 1.10 in. (28 mm) to about 1.18 in. (30 mm), and apitch P of about 0.65 in. (16.50 mm) to about 0.68 in. (17.33 mm) at apitch angle of from about 45° to about 60°.

Still referring to FIGS. 3a, 3b and 3c, the width of the raised bondingpoints 72 on the outer surface 74 of the upper roll 70 can range fromabout 0.028 in. (0.70 mm) to about 0.031 in. (0.80 mm), with a width ofabout 0.030 (0.75 mm) being suitable. As is conventional in the art, thewidth at the base 76 of the raised bonding points 72 is slightly greaterthan the width on the outer surface 74. The raised bonding points 72 ofthe upper roll 70 can have an engraving depth of about 0.026 in. (0.65mm). The individual raised bonding points 72 in this embodiment arearranged at about 218.0 bonding points/in² (33.8 bonding points/cm²) andhave a repeating width W' of about 0.094 in. (2.4 mm) to about 0.118 in.(3.0 mm), a repeating height H' of about 0.068 in. (1.72 mm), and apitch P' of about 0.068 in. (1.72 mm) at a pitch angle of from about 30°to about 45°. While in the embodiment shown, the outer surface 74 of theraised bonding points 72 is in the form of a square, other geometric andnon-geometric shapes may be employed as the raised bonding points 72 ofupper roll 70.

The inventor has observed in optimizing the nonwoven material 10 of thepresent invention, the following factors are interrelated:

1) Temperature of bonding rolls 60 and 70;

2) Line speed of the forming process;

3) Nip pressure between the bonding rolls;

4) Diameter of the bonding rolls; and

5) Types of materials used in forming layers 12 and 22.

That is, modifying one or more of the above factors tends to affect theremaining factors as well. For example, an increase in the line speed ofthe forming process results in the layers of the nonwoven laminate beingin contact with the bonding rolls for a shorter period of time.Consequently, the temperature of the bonding rolls may have to beincreased to achieve the required degree of bonding of the two layers,thereby compensating for the change in line speed.

As noted above, an important factor relating to the bonding of the twolayers is the temperature at which the bonding rolls 60 and 70 aremaintained. Naturally, temperatures below a certain point for eachpolymer will not effect any bonding, while temperatures above anotherpoint will melt too much of the web. Also, its has been observed thatthe temperature of the bonding rolls can affect both the tensilestrength and softness of the nonwoven laminate produced. In particular,within a certain range, higher temperatures will produce a web withhigher tensile strength. However, these same higher temperatures canproduce a web with decreased softness. This is likely due to a higherand lower degree of bonding that occurs within this range oftemperatures. That is, the higher temperatures likely result in more andstronger interfilament bonding that is beneficial to tensile strengthand somewhat detrimental to softness. In addition, higher temperatureslikely result in a less lofty, pillowed structure, as the thermoplasticfibers experience more shrinkage, adversely affecting the softness andcushiony feel of the nonwoven material 10.

It has further been observed that the temperature of the rolls canaffect the formation of apertures in the bonded areas of the web. Whilethe apertures formed in the bonded areas are not solely thermallyproduced, thermal bonding allows the respective layers to be compressedto a sufficient degree that mechanical aperturing may occur, as furtherdescribed below.

In the embodiment shown, the bonding temperature for lower roll 60 canrange from about 260° F. (127° C.) to about 285° F. (141° C.), with atemperature of about 265° F. (129° C.) to about 275° F. (135° C.) beingdesireable, and the bonding temperature for upper roll 70 can range fromabout 270° F. (132° C.) to about 320° F. (160° C.), with a temperatureof about 290° F. (143° C.) to about 315° F. (157° C.) being desireable.It is important that the bonding roll that contacts the first nonwovenlayer 12, which in this embodiment is lower bonding roll 60, have alower temperature than the bonding roll that contacts the secondnonwoven layer 22, which in this embodiment is upper roll 70, such thatthe softness of the first layer 12 is not significantly reduced, whilethe thermoplastic fibers in the second layer 22 are sufficiently heatedto thermally fuse with the thermoplastic fibers in the first layer 12.So long as the temperature of bonding roll 60 is maintained at aslightly lower temperature than the temperature at which the first layer12 is bonded, assuming all other operating parameters are constant forthe forming process described above, the softness of layer 12 will notchange significantly.

Another important factor relating to the bonding of the two layers aswell as the formation of apertures in the bonding regions is the linespeed at which the respective bonding rolls are operated. In theembodiments shown, the rolls can operate at line speeds ranging fromabout 65 feet/in. (20 m/min.) to about 328 feet/min. (100 m/min.) ormore. It has further been observed that aperture formation within thebonding regions can be significantly improved by employing differentrotational surface speeds for the two bonding rolls. The difference inrotational surface speeds can differ from about 4% to about 20%, withabout 5% to about 15% being conveniently employed. Either bonding rollmay be employed with a higher rotational speed than the other bondingroll. While not wishing to be bound by any particular theory, it isbelieved that aperture formation is improved by operating the bondingrolls at different rotational speeds because the shearing forcestangential to the bonding roll surfaces in the thermally producedcompacted bonding areas tear (mechanical aperturing) the nonwovenmaterials at the points of contact between the raised bonding patternsof the bonding rolls.

Another important factor relating to the bonding of the two layers isthe diameter of each bonding roll. While in the embodiment shown (and inthe ensuing Examples), the bonding rolls each are about 12 inches (305mm) in diameter, bonding rolls having smaller or larger diameters aresuitable for producing the nonwoven laminate of the present invention.Moreover, the diameters of the bonding rolls need not be identical.

Another important factor relating to the bonding of the two layers andaperture formation within the bonding regions is the nip pressurebetween the bonding rolls. In the embodiment shown, the bonding rollsproduce a nip pressure of from about 60 pli (10 kg/lcm) to about 400 pli(67 kg/lcm). It is likely that higher nip pressures will result in aless lofty, pillowed structure, adversely affecting the softnesscharacteristics of the nonwoven material 10.

In the embodiment shown, after the layers 12 and 22 of nonwovenlaminated material 10 are bonded by bonding rolls 60 and 70, nonwovenmaterial 10 is wound on a take up roll (winder) 78. Alternatively, itmay be desirable to design this apparatus to connect with a fabricationline for the end product. Higher tension on the take up roll 78 orfabrication line is another factor that is likely to adversely affectthe loftiness of the nonwoven material 10 of this invention.

FIG. 4 is a cross-sectional view through a disposable diaper 100including the nonwoven material 80 of the present invention positionedon the side of the diaper that will be placed next to the infant's body.In the embodiment shown, the nonwoven material 80 forms a body facingouter layer 12 comprising a bonded carded web formed of polypropylenefibers and an inner "surge" layer 22 comprising a substantially unbondedor unbonded carded web formed of a blend of polypropylene and polyesterfibers as described above. The diaper further includes aliquid-permeable bodyside liner 82 formed, for example, of nonwovenspunbond or bonded carded web material, an absorbent core 84 formed, forexample, of a blend of hydrophilic cellulosic woodpulp fluff and highlyabsorbent gelling particles (e.g., superabsorbents), a tissue layer 92surrounding at least a portion of absorbent core 84, and a flexible,liquid-impermeable outer cover 86 formed, for example, of thinpolyethylene film. As used herein, the term "superabsorbent" refers to amaterial, natural or synthetic, capable of absorbing or gelling at leastabout 10 times its weight in liquid.

In the embodiment shown, the nonwoven material 80, which overlies liner82, is substantially coextensive with the width of absorbent core 84,while the total area of liner 82 is substantially coextensive with thetotal area of outer cover 86. Alternatively, the nonwoven material 80may be arranged to be generally coextensive with the outer cover 86. Inother configurations, nonwoven material 80 may have a width that is lessthan the minimum width of absorbent core 84. In various optionalconfigurations, the length of nonwoven material 80 may be equal to orless than the length of outer cover 86, although in the illustratedembodiment, the lengths of nonwoven material 80 and outer cover 86 aresubstantially equal.

As further shown in FIG. 4, nonwoven material 80 is positioned betweentwo optional containment flaps 88 attached to the bodyside surface ofliner 82. Suitable constructions and arrangements for containment flapsare described, for example, in U.S. Pat. No. 4,704,116, issued Nov. 3,1987, to K. Enloe, the disclosure of which is hereby incorporated byreference.

Elastic members 90, which may optionally be included in the absorbentarticle, are disposed adjacent each longitudinal edge of diaper 100.Elastic members 90 are arranged to draw and hold the lateral, sidemargins of diaper 100 against the legs of the wearer. Additionally,elastic members (not shown) also may be disposed adjacent either or bothof the end edges of diaper 100 to provide an elasticized waistband.

Nonwoven material 80 is connected to or otherwise associated withbodyside liner 82 or outer cover 86 in an operable manner. As usedherein, the term "associated" encompasses configurations where nonwovenmaterial 80 is directly joined to bodyside liner 82 by affixing marginalareas or intermediate areas of nonwoven material 80 directly to liner82, and configurations where nonwoven material 80 is joined to outercover 86, either directly or by affixing nonwoven material 80 tointermediate components that in turn are affixed to outer cover 86.Nonwoven material 80 may be affixed directly to bodyside liner 82 orouter cover 86 by attachment means (not shown) such as adhesive, sonicbonds, thermal bonds or any other attachment means known to those ofordinary skill in the art. It is readily apparent that such attachmentmeans may also be used to interconnect and assemble together the othercomponent parts of the diaper 100. Fastening means (not shown) of knownconstruction may also be optionally incorporated in the diaperconstruction shown.

While a particular configuration of the component parts of diaper 100 isshown in FIG. 4, these components may be assembled into a variety ofwell-known diaper configurations. It should be further recognized,however, that in disposable absorbent articles other than diapers,individual components may be optional, depending upon their intended enduses.

An important property of any bodyside liner material is its softness. Inparticular, it is important for the liner to be both extremely pliableas well as soft to the touch in consideration of the infant's comfort.The present inventor has observed that the body facing layer 12 of thenonwoven material 80 of the present invention exhibits excellentsoftness characteristics.

Another important property of a nonwoven liner and nonwoven fabrics ingeneral is tensile strength, i.e., the resistance to tearing, andpercent elongation prior to tearing. These properties have been measuredby the present inventor on a device, such as the Instron Model TM 1000(Instron Corp. having offices in Canton Mass.), that grips a sample(about 1×6 in. (25.4×1524 mm)) of a nonwoven fabric in a pair of jawsextending the entire width of the sample, and then pulls it apart at aconstant rate of extension. The force needed to rupture the fabric isrecorded as the tensile strength and the length of the fabric beforerupture as compared to the original length provides the percentelongation value. These tests can be performed either with the fabricoriented in the jaws so that the force is applied in the machinedirection, MD, or with the fabric oriented so that the force is appliedin the cross direction, CD. It was observed that the nonwoven materialsmade in accordance with the present invention, several examples of whichare discussed below, exhibited sufficient tensile strength and percentelongation properties.

Yet another property that is particularly important for a liner of anabsorbent article, such as a disposable diaper, is the wettability ofthe liner. Depending upon the design of the absorbent article, it isusually desirable to have the liner be at least partially wettable inorder to facilitate passage of liquid through to the absorbent core. Inaddition, it is even more desirable to provide a wettability gradient inthe liner whereby liquid can be wicked away from the wearer forincreased comfort and skin health. In particular, it is desireable toprovide, as in the present invention, a body facing layer 12 that isless wettable than the "surge" layer 22, i.e., the layer closest to theabsorbent material. In this way, liquid flows more easily through to theabsorbent core material than it flows back to the wearer.

Many of the polymers that are suitable to make nonwoven webs arehydrophobic. Specifically, polyolefin fibers are completely hydrophobic.As a result, it is desirable for nonwoven webs made with these polymersto impart a desired level of wettability and hydrophilicity. It is knownin the art that wettability of hydrophobic fibers, such aspolypropylene, can be increased by the application of water-solublefinishes, typically ranging from about 0.3% to about 0.6%, to thesurfaces of such hydrophobic fibers for improving the liquid managementproperties of such fibers in their end-use applications. In theembodiment described herein, the polypropylene fibers employed can bemade wettable by treating the fibers with water-soluble finishes beforebeing formed into nonwoven layers 12 and 22.

Another contributing factor in producing the described wettabilitygradient is the blending of polyester fibers in a desired amount withthe polypropylene fibers forming the second nonwoven layer 22. Asdescribed above, the differing pore sizes resulting from using thecoarser, more resilient polyester fibers in a homogeneous blend ofpolypropylene and polyester fibers in nonwoven layer 22, produce therequired wettability gradient between first layer 12 and second layer22.

The following examples are provided to give a more detailedunderstanding of the invention. The particular compositions,proportions, materials and parameters are exemplary and are not intendedto specifically limit the scope of the present invention.

EXAMPLES Example 1

A first layer was formed of 100% polypropylene (PP-196 manufactured byHercules, Inc. having offices in Wilmington, Del.) by blending on aconventional carding machine as described above. The first layer had abasis weight of about 18 g/m² (0.5 oz/yd²). A second layer was formed of60% polyester (SD-10 manufactured by Sam Yang having offices in Seoul,South Korea) and 40% PP-196 polypropylene by blending on a conventionalcarding machine. The second layer had a basis weight of about 32 g/m²(0.9 oz/yd²). The first and second layers were thermobonded together byheated bonding rolls as shown in FIGS. 3 and 3a., with the bonding rollcontacting the first layer maintained at a temperature of about 272° F.(133° C.) and the bonding roll contacting the second layer maintained ata temperature of about 315° F. (157° C.) The line speed for the bondingrolls was about 80 ft/min. (24 m/min.) and the nip pressure between thebonding rolls was about 300 pli. The thermobonding process yielded anonwoven laminated material having a spaced apart bonding pattern withapertures formed within the bonding regions and a percent bond area ofabout 2%.

Example 2

A first layer was formed of 100% PP-196 polypropylene by blending on aconventional carding machine as described above. The first layer had abasis weight of about 18 g/m² (0.5 oz/yd²). A second layer was formed of60% polyester (PET-295 manufactured by Hoechst Celanese having officesin Greenville, S.C.) and 40% PP-196 polypropylene by blending on aconventional carding machine. The second layer had a basis weight ofabout 32 g/m² (0.9 oz/yd²). The first and second layers werethermobonded together by heated bonding rolls as shown in FIGS. 3 and3a., with the bonding roll contacting the first layer maintained at atemperature of about 272° F. (133° C.) and the bonding roll contactingthe second layer maintained at a temperature of about 315° F. (157° C.)The line speed for the bonding rolls was about 80 ft/min. (24 m/min.)and the nip pressure between the bonding rolls was about 300 pli. Thethermobonding process yielded a nonwoven laminated material having aspaced apart bonding pattern with apertures formed within the bondingregions and a percent bond area of about 2%.

Example 3

A first layer was formed of 100% polypropylene fibers (PT110-20 suppliedby Lohmann GmbH & Co. KG having offices in Neuwied, Germany). The firstlayer had a basis weight of about 20 g/m² (0.5 oz/yd²). A second layerwas formed of 60% polyester (PET-292 manufactured by Hoechst/AG havingoffices in Frankfurt, Germany) and 40% polypropylene (PP-71 "SOFT-71"manufactured by Danaklon A/S, Inc. having offices in Varde, Denmark) byblending on a conventional carding machine as described above. Thesecond layer had a basis weight of about 32 g/m² (0.9 oz/yd²). The firstand second layer were thermobonded together by heated bonding rolls asshown in FIGS. 3 and 3a., with the bonding roll contacting the firstlayer maintained at a temperature of about 272° F. (133° C.) and thebonding roll contacting the second layer maintained at a temperature ofabout 315° F. (157° C.) The line speed for the bonding rolls was about80 ft/min. (24 m/min.) and the nip pressure between the bonding rollswas about 300 pli. The thermobonding process yielded a nonwovenlaminated material having a spaced apart bonding pattern with aperturesformed within the bonding regions and a percent bond area of about 2%.

Example 4

A first layer was formed of 100% PP-71 polypropylene using aconventional spunbonding forming process. The first layer had a basisweight of about 22 g/m² (0.6 oz/yd²). A second layer was formed of 60%polyester PET-292 and 40% PP-71 polypropylene by blending on aconventional carding machine. The second layer had a basis weight ofabout 32 g/m² (0.9 oz/yd²). The first and second layer were thermobondedtogether by heated bonding rolls as shown in FIGS. 3 and 3a., with thebonding roll contacting the first layer maintained at a temperature ofabout 272° F. (133° C.) and the bonding roll contacting the second layermaintained at a temperature of about 315° F. (157° C.) The line speedfor the bonding rolls was about 80 ft/min. (24 m/min.) and the nippressure between the bonding rolls was about 300 pli. The thermobondingprocess yielded a nonwoven laminated material having a spaced apartbonding pattern with apertures formed within the bonding regions and apercent bond area of about 2%.

Example 5

A first layer was formed of 100% polypropylene (75% PP-196 and 25%PP-190, both manufactured by Hercules, Inc. having offices inWilmington, Del.) by blending on a conventional carding machine asdescribed above. The first layer had a basis weight of about 18 g/m²(0.5 oz/yd²). A second layer was formed of 60% PET-292 polyester and 40%PP-71 polypropylene by blending on a conventional carding machine. Thesecond layer had a basis weight of about 32 g/m² (0.9 oz/yd²). The firstand second layer were thermobonded together by heated bonding rolls asshown in FIGS. 3 and 3a., with the bonding roll contacting the firstlayer maintained at a temperature of about 272° F. (133° C.) and thebonding roll contacting the second layer maintained at a temperature ofabout 315° F. (157° C.) The line speed for the bonding rolls was about80 ft/min. (24 m/min.) and the nip pressure between the bonding rollswas about 300 pli. The thermobonding process yielded a nonwovenlaminated material having a spaced apart bonding pattern with aperturesformed within the bonding regions and a percent bond area of about 2%.

Example 6

A first layer was formed of 100% PP-196 polypropylene by blending on aconventional carding machine as described above. The first layer had abasis weight of about 18 g/m² (0.5 oz/yd²). A second layer was formed of60% PET-295 polyester and 40% PP-196 polypropylene by blending on aconventional carding machine. The second layer had a basis weight ofabout 32 g/m² (0.9 oz/yd²). The first and second layers werethermobonded together by heated bonding rolls as shown in FIGS. 3 and3a., with the bonding roll contacting the first layer maintained at atemperature of about 272° F. (133° C.) and the bonding roll contactingthe second layer maintained at a temperature of about 315° F. (157° C.)The line speed for the bonding rolls was about 80 ft/min. (24 m/min.)and the nip pressure between the bonding rolls was about 300 pli. Thethermobonding process yielded a nonwoven laminated material having aspaced apart bonding pattern with apertures formed within the bondingregions and a percent bond area of about 2%.

The resultant nonwoven laminated materials of the above examples had theproperties set forth in the following table:

                  TABLE I                                                         ______________________________________                                               Basis   Thick-         Tensile   %                                            Weight  ness    Density                                                                              (g/in.)   Elongation                            Example                                                                              (g/m.sup.2)                                                                           (in.)   (g/cc) MD    CD    MD                                  ______________________________________                                        1      49.0    0.046   0.041  1578.0                                                                              196.0 33.2                                2      52.0    0.046   0.044  1585.0                                                                              198.0 32.0                                3      51.0    0.048   0.042  2672.0                                                                              402.0 29.2                                4      56.5    0.051   0.043  1439.0                                                                              382.0 26.1                                5      51.2    0.057   0.034  1509.0                                                                              228.0 39.6                                6      51.5    0.058   0.035  1610.0                                                                              263.0 37.3                                ______________________________________                                    

For the purposes of the present disclosure, the following testprocedures can be used to determine particular parameters of thenonwoven material 10 of the present invention.

The Fluid Intake and Flowback Evaluation (FIFE) test has been designedto measure the absorbency/penetration time, flowback amount and amountof liquid retention in the liner of a disposable absorbent article. Theabsorbency/penetration time (in seconds) is measured by using astopwatch and visually determining the length of time required to absorbsimulated urine voidings. The flowback test measures, in grams, theamount of liquid that emerges from the "user side" of the absorbentarticle after it has absorbed each of three liquid insults and pressurehas been applied.

The apparatus shown in FIGS. 7 and 8 is used for this test. A samplediaper to be tested, as shown in FIG. 4 and shown in phantom at 102 inFIG. 7, is weighed to the nearest 0.1 g. The sample 102 is prepared bycutting the leg and waist elastic members and containment flap elastics(not shown) along their length in order to allow the sample to lie flat.Sample dimensions, weight and density profiles of the sample 102 andcomposition of the absorbent core must be appropriately controlled toobtain valid results. Data reported herein were obtained from 12 in.×12in. (305 mm.×305 mm.) rectangular samples including the nonwovenmaterials 10 described above in Examples 4, 5 and 6 and absorbent corescontaining about 10 grams of woodpulp fluff and about 12 grams ofsuperabsorbent material, such as DOW DRYTECH 835 or an equivalentthereof.

The sample 102 is placed flat and smooth under an 880 g. cylinder plateassembly 104 such that the cylinder 106, which has a 5.1 cm i.d., endsup in a designated location 108. For example, the designated location108 can range from about 41/2 inches (114.3 mm.) to about 53/4 inches(146.1 mm.) from the edge of the sample 102, depending upon the size(e.g., small (s), medium (m), large(l) or extra large(xl)) of theabsorbent article to be tested. Under the sample 102 is a raisedplatform 110 that is 1/2 inch (12.7 mm.) high (d)×6 inches (152.4 mm.)long (e)×3 inches (76.2 mm.) wide (f). Also, the cylinder 106 extends adistance (g) of about 1/32 inch (0.8 mm.) below the cylinder plateassembly 104.

Funnel 112 on top of cylinder 106 is perpendicular to the sample 102 andcentered on the designated location 108. A specified amount of syntheticurine (e.g., 50 ml, 80 ml or 100 ml for small, medium and large or extralarge diapers, respectively), is poured through the funnel 112. (Anexample of a suitable synthetic urine is Item No. K-C 399105, availablefrom PPG Industries having offices in Appleton, Wis.) The time elapsingbetween the first liquid contact with the sample 102 and the time whenliquid no longer is visible on the surface of the sample 102 is measuredwith a stop watch. One minute after the initial liquid insult isimbibed, a second insult of the same size is introduced. The time toimbibe the second insult of liquid is measured as for the first insult.

Referring now to FIGS. 9 and 10, one minute after the second insult isimbibed, the sample 102 is placed on a vacuum apparatus 114 and coveredwith blotter paper 116 together with liquid impervious latex sheeting118. A 35,000 dyne/cm² (about 0.5 psi) vacuum pressure then is appliedto suck the impervious latex sheeting 118 onto the blotter 116 andsample 102 for two minutes. After the pressure is released, the wetblotter paper 116 then is weighed. The increase in weight (in grams) ofthe blotter paper 116 represents the flowback.

Within one minute after the pressure is released from the sample 102, athird liquid insult is introduced and timed as described above. Theliquid intake time then is the number of seconds for the prescribedamount of liquid (80 ml for the results described herein) to enter thesample 102.

Samples 102 including the nonwoven laminated materials of the aboveExamples 4, 5 and 6 had the flowback and liquid intake time values setforth in the following table:

                  TABLE II                                                        ______________________________________                                                       FIFE Liquid                                                                             FIFE                                                                Intake Time                                                                             Flowback                                             Example        (seconds) (grams)                                              ______________________________________                                        4              33        7.1                                                  5              34        1.9                                                  6              30        3.2                                                  ______________________________________                                    

While the Fluid Intake and Flowback Evaluation test results areindicated above for several specific Examples, absorbent articlesincorporating the nonwoven material 10 described herein can have liquidintake times ranging from about 11 seconds to about 38 seconds andflowback values ranging from about 1.0 gram to about 9.0 grams.

It is contemplated that the nonwoven material 10 constructed inaccordance with the present invention will be tailored and adjusted bythose of ordinary skill in the art to accommodate various levels ofperformance demand imparted during actual use. For example, mild urinaryincontinence and menstrual flow pads involve different delivery rates,volumes and timing than infant urine insults. Moreover, the liquid inthe surge can vary in terms of the liquid viscosity, surface tension,temperature and other physical properties that could affect theperformance of the nonwoven material 10 in the various actual productend usages. Accordingly, while this invention has been described byreference to the above embodiments and examples, it will be understoodthat this invention is capable of further modifications. Thisapplication is, therefore, intended to cover any variations, uses oradaptations of the invention following the general principles thereof,and including such departures from the present disclosure as come withinknown or customary practice in the art to which this invention pertainsand fall within the limits of the appended claims.

I claim:
 1. An apparatus for forming a laminated fibrous materialcomprising:means for providing a fibrous layer comprising a plurality offibers or filaments of one or more thermoplastic polymeric materials;means for providing a second fibrous layer comprising a plurality offibers or filaments of two or more thermoplastic polymeric materials;means for bonding said first and second layers at an interface betweensaid layers in a spaced apart bonding pattern comprising compactedbonding regions having a first degree of bonding separated by second,lesser bonded fiber spans; said bonding means comprising a first thermalbonding roll and a second thermal bonding roll opposedly positionedrelative to each other, each of said bonding rolls having an outersurface in contact with one of said first and second layers of saidfirst and second layers passing therebetween, said first and secondbonding rolls having different raised bonding patterns on said outersurfaces thereof, said first bonding roll having a spaced apart raisedbonding pattern on the outer surface thereof and said second bondingroll having a plurality of raised bonding points on the outer surfacethereof; means for operating said first bonding roll at a firstrotational speed and means for operating said second bonding roll at asecond rotational speed, said operating means ensuring that said firstand second rotational speeds differ within a range of from about 4percent to about 50 percent; means for maintaining said first bondingroll at a first bonding temperature within the range of from about 260°F. to about 285° F. and means for maintaining said second bonding rollat a second bonding temperature within the range of from about 270° F.to about 320° F., said maintaining means maintaining said first andsecond bonding rolls at different bonding temperatures; and said bondingrolls forming apertures within said bonding regions, said aperturesbeing substantially free of fibers through the thickness of saidlaminated fibrous material.
 2. An apparatus for forming a laminatedfibrous material according to claim 1 further comprising first bondingmeans for bonding fibers of said first fibrous layer to one another. 3.An apparatus for forming a laminated fibrous material according to claim1 wherein the formation of said apertures is substantially limited tosaid bonding regions.
 4. An apparatus for forming a laminated fibrousmaterial according to claim 1 wherein said bonding means bonds saidfirst and second layers together in a spaced apart bonding pattern suchthat the resulting laminated fibrous material has a percent bond area offrom about 1% to about 6%.
 5. An apparatus for forming a laminatedfibrous material according to claim 1 wherein said spaced apart bondingpattern is formed by points of contact between said raised bondingpatterns on said outer surfaces of said first and second bonding rolls.6. An apparatus for forming a laminated fibrous material according toclaim 5 wherein said apertures are formed by points of contact betweensaid raised bonding patterns on said outer surfaces of said first andsecond bonding rolls.
 7. An apparatus for forming a laminated fibrousmaterial according to claim 1 wherein said first bonding roll has apercent bond area of from about 9 percent to about 20 percent and saidsecond roll has a percent bond area of from about 10 percent to about 30percent.
 8. An apparatus for forming a laminated fibrous materialaccording to claim 1 wherein said raised bonding patterns of said firstand second bonding rolls are configured to optimize the number of saidapertures formed within said bonding regions.
 9. An apparatus forforming a laminated fibrous material according to claim 1 wherein saidfirst bonding temperature ranges from about 265° F. to about 275° F. andsaid second bonding temperature ranges from about 290° F. to about 315°F.
 10. An apparatus for forming a laminated fibrous material accordingto claim 1 wherein said first fibrous layer contacts said first bondingroll and said second fibrous layer contacts said second bonding rollduring rotation and heating of said rolls.
 11. An apparatus for forminga laminated fibrous material according to claim 1 wherein said operatingmeans rotate said first and second bonding rolls such that said firstand second fibrous layers passing therebetween have a line speed rangingfrom about 20 meters per minute to about 100 meters per minute.
 12. Anapparatus for forming a fibrous material according to claim 1 furthercomprising means for producing a nip pressure of from about 60 poundsper linear inch to about 400 pounds per linear inch within a nip formedbetween said first and second bonding rolls.